1. Field of the Invention
This invention relates to sulfur- and nitrogen-containing compositions and in a more particular sense it relates to those compounds having a thiocarbamyl moiety adapted for use as additives in hydrocarbon oils. This invention relates also to hydrocarbon oils, especially lubricating oil compositions containing said sulfur- and nitrogen-containing compositions.
2. General Background
The problem of deterioration of hydrocarbon oils has been the cause of principal concern in the formulation of hydrocarbon oil compositions such as fuels and lubricating compositions. Deterioration of hydrocarbon oils results in the formation of products which are corrosive to the metal surfaces with which the oils come into contact. It results also in the formation of products which have a tendency to agglomerate to form sludge and varnish-like deposits.
In recent years it has been a common practice to incorporate into hydrocarbon oils chemical additives which are capable of inhibiting the deterioration of oil and the formation of these harmful deposits. Such additives have generally been classified into three principal groups according to the manner in which they function to improve hydrocarbon oil. One group of such additives are the oxidation inhibitors which function to stabilize the oil against oxidative degradation. Another group of such additives are the corrosion inhibitors which counteract the corrosiveness of the products of oil degradation or passivate the metal surfaces against the corrosive action of such products. Still another group of such additives are the detergents or dispersing agents which function to maintain products of oil degradation in dispersion in the oil phase and to prevent the deposition of sludge and varnish.
Two or more such additives are often needed in a hydrocarbon oil to stabilize the oil against formation of harmful degradation products. The incorporation in an oil, however, of several different types of additives not only is costly, but is also dependent upon the compatibility of the additives with one another. Thus, it is known that additives which are effective separately may not be used in combination because of their incompatibility. A great deal of effort has recently been devoted to the development of so-called "multifunctional" additive, i.e., an additive which, by itself, is capable of imparting several desirable properties to an oil. It will be readily appreciated that the use of such additive is highly advantageous from the standpoint of both economy and convenience.
3. Prior Art Publications
Sulfur- and nitrogen-containing compositions are stated to provide such desirable multifunctional activity to both fuels and lubricating oils. For example, in U.S. Pat. No. 2,168,674 to Loane et al, mineral oils containing fatty acid thiocyanates, such as lauroyl thiocyanate and stearoyl thiocyanate, have been suggested as oxidation inhibitors for lubricating oils; in U.S. Pat. No. 2,169,700, the same inventors have disclosed mineral oils containing polythiocyanates having the formula, R(SCN).sub.n, wherein R is an aliphatic radical or an aromatic radical, and n is an integer greater than one; and, in U.S. Pat. Nos. 2,619,464 and 2,680,759 it is reported that mineral lubricating oils containing small amounts of high molecular weight alkyl monothiocyanates, preferably C.sub.21 -C.sub.34 monothiocyanates as paraffin wax monothiocyanates, are resistant to oxidation and have a reduced tendency to corrode hard metal alloy bearings (the polythiocyanates are noted as ineffective due to their substantial insolubility in mineral lubricating oils). The referenced latter compositions are produced by the reaction of an alkyl chloride with an inorganic salt of thiocyanic acid, e.g. ammonium thiocyanate, at a temperature of at least 100.degree. C.
U.S. Pat. No. 3,330,763 discloses the use of hydrocarbylamine salts of thiocyanic acid as load-carrying additives in lubricating oils.
Further, the isomerization of allylic thiocyanates has been attributed to the occurrence of a cyclic intromolecular transition state (Organic Sulfur Compounds edited by N. Kharasch, Vol. 1, pg. 312, 1961, Pergamon Press, N.Y.).
It is, accordingly, an object of this invention to provide novel compositions of matter.
It is also an object of this invention to provide compositions adapted for use as multifunctional additives in hydrocarbons, particularly for fuels and oils.
It is also an object of this invention to provide compositions useful as corrosion, oxidation inhibitors and/or dispersants in hydrocarbon lubricating oils.